In each of the top 10 richest cities, residents have combined wealth of at least $1 trillion, and as much as $3 trillion. Total private wealth includes all assets — property, cash, equities, and business interests — minus any liabilities.

According to New World Wealth's research, total private wealth is "a far better gauge of the financial health" of an economy than GDP. Ultimately, the wealth of a public signifies its spending power.

To be sure, these cities rank highly because of two factors: a large general population and a significant amount of high-net-worth residents. Across the world, there are about 15.2 million people with net assets of $1 million or more, while the average person has net assets of $28,400.

Below, check out the top 10 richest places in the world ranked by total private wealth of all residents.